Simplify the following expression: $k = \dfrac{a}{6} + \dfrac{a}{5}$
Solution: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $6$ and $5$ $\lcm(6, 5) = 30$ $ k = \dfrac{5}{5} \cdot \dfrac{a}{6} + \dfrac{6}{6} \cdot \dfrac{a}{5} $ $k = \dfrac{5a}{30} + \dfrac{6a}{30}$ $k = \dfrac{5a +6a}{30}$ $k = \dfrac{11a}{30}$